By Art Reisman – CTO – www.netequalizer.com
When it comes to how much money to spend on the Internet, there seems to be this underlying feeling of guilt with everybody I talk to. From ISPs, to libraries or multinational corporations, they all have a feeling of bandwidth inadequacy. It is very similar to the guilt I used to feel back in College when I would skip my studies for some social activity (drinking). Only now it applies to bandwidth contention ratios. Everybody wants to know how they compare with the industry average in their sector. Are they spending on bandwidth appropriately, and if not, are they hurting their institution, will they become second-rate?
To ease the pain, I was hoping to put a together a nice chart on industry standard recommendations, validating that your bandwidth consumption was normal, and I just can’t bring myself to do it quite yet. There is this elephant in the room that we must contend with. So before I make up a nice chart on recommendations, a more relevant question is… how bad do you want your video service to be?
Your choices are:
- downright awful
Although my answer may seem a bit sarcastic, there is a truth behind these choices. I sense that much of the guilt of our customers trying to provision bandwidth is based on the belief that somebody out there has enough bandwidth to reach some form of video Shangri-La; like playground children bragging about their father’s professions, claims of video ecstasy are somewhat exaggerated.
With the advent of video, it is unlikely any amount of bandwidth will ever outrun the demand; yes, there are some tricks with caching and cable on demand services, but that is a whole different article. The common trap with bandwidth upgrades is that there is a false sense of accomplishment experienced before actual video use picks up. If you go from a network where nobody is running video (because it just doesn’t work at all), and then you increase your bandwidth by a factor of 10, you will get a temporary reprieve where video seems reliable, but this will tempt your users to adopt it as part of their daily routine. In reality you are most likely not even close to meeting the potential end-game demand, and 3 months later you are likely facing another bandwidth upgrade with unhappy users.
To understand the video black hole, it helps to compare the potential demand curve pre and post video.
A quality VOIP call, which used to be the measuring stick for decent Internet service runs about 54kbs. A quality HD video stream can easily consume about 40 times that amount.
Yes, there are vendors that claim video can be delivered at 250kbs or less, but they are assuming tiny little stop action screens.
Couple this tremendous increase in video stream size with a higher percentage of users that will ultimately want video, and you would need an upgrade of perhaps 60 times your pre-video bandwidth levels to meet the final demand. Some of our customers, with big budgets or government subsidized backbones, are getting close but, most go on a honeymoon with an upgrade of 10 times their bandwidth, only to end up asking the question, how much bandwidth do I really need?
So what is an acceptable contention ratio?
- Typically in an urban area right now we are seeing anywhere from 200 to 400 users sharing 100 megabits.
- In a rural area double that rati0 – 400 to 800 sharing 100 megabits.
- In the smaller cities of Europe ratios drop to 100 people or less sharing 100 megabits.
- And in remote areas served by satellite we see 40 to 50 sharing 2 megabits or less.
How Much YouTube Can the Internet Handle?November 21, 2008 — netequalizer
By Art Reisman, CTO, http://www.netequalizer.com
As the Internet continues to grow and true speeds become higher, video sites like YouTube are taking advantage of these fatter pipes. However, unlike the peer-to-peer traffic of several years ago (which seems to be abating), YouTube videos don’t face the veil of copyright scrutiny cast upon p2p which caused most users to back off.
In our experience, there are trade offs associated with the advancements in technology that have come with YouTube. From measurements done in our NetEqualizer laboratories, the typical normal quality YouTube video needs about 240kbs sustained over the 10 minute run time for the video. The newer higher definition videos run at a rate at least twice that.
Many of the rural ISPs that we at NetEqualizer support with our bandwidth shaping and control equipment have contention ratios of about 300 users per 10-megabit link. This seems to be the ratio point where these small businesses can turn a profit. Given this contention ratio, if 40 customers simultaneously run YouTube, the link will be exhausted and all 300 customers will be wishing they had their dial-up back. At last check, YouTube traffic accounted for 10 percent of all Internet Traffic. If left completely unregulated, a typical rural ISP could find itself on the brink of saturation from normal YouTube usage already. With tier-1 providers in major metro areas there is usually more bandwidth, but with that comes higher expectations of service and hence some saturation is inevitable.
If you believe there is a conspiracy, or that ISPs are not supposed to profit as they take risk and operate in a market economy, you are entitled to your opinion, but we are dealing with reality. And there will always be tension between users and their providers, much the same as there is with government funds and highway congestion.
The fact is all ISPs have a fixed amount of bandwidth they can deliver and when data flows exceed their current capacity, they are forced to implement some form of passive constraint. Without them many networks would lock up completely. This is no different than a city restricting water usage when reservoirs are low. Water restrictions are well understood by the populace and yet somehow bandwidth allocations and restrictions are perceived as evil. I believe this misconception is simply due to the fact that bandwidth is so dynamic, if there was a giant reservoir of bandwidth pooled up in the mountains where you could see this resource slowly become depleted , the problem could be more easily visualized.
The best compromise offered, and the only comprise that is not intrusive is bandwidth rationing at peak hours when needed. Without rationing, a network will fall into gridlock, in which case not only do the YouTube videos come to halt , but so does e-mail , chat , VOIP and other less intensive applications.
There is some good news, alternative ways to watch YouTube videos.
We noticed during out testing that YouTube videos attempt to play back video as a real-time feed , like watching live TV. When you go directly to YouTube to watch a video, the site and your PC immediately start the video and the quality becomes dependent on having that 240kbs. If your providers speed dips below this level your video will begin to stall, very annoying; however if you are willing to wait a few seconds there are tools out there that will play back YouTube videos for you in non real-time.
They accomplish this by pre-buffering before the video starts playing. We have not reviewed any of these tools so do your research. We suggest you google “YouTube buffering tools” to see what is out there. Not only do these tools smooth out the YouTube playback during peak times or on slower connections , but they also help balance the load on the network during peak times.
Bio Art Reisman is a partner and co-founder of APconnections, a company that provides bandwidth control solutions (NetEqualizer) to ISPs, Universities, Libraries, Mining Camps and any organization where groups of users must share their Internet resources equitably. What follows is an objective educational journey on how consumers and ISPs can live in harmony with the explosion of YouTube video.